The purpose of this study is to determine in subjects with Type I DM: 1) Whether glycemic control can be achieved at least as effectively with: an intensive insulin regimen involving pre-meal inhaled insulin plus twice daily SQ NPH insulin as compared with an intensive SQ insulin regimen involving pre-meal regular insulin plus twice daily NPH, given as 4 injections per day. 2) The toleration and safety of inhaled insulin therapy and its effects after 6 months, if any, on measures of pulmonary function.